Turbine engines currently play a dominant role in systems including power generation and aircraft propulsion. Current turbine designs have been limited by the lack of sensors capable of reliably providing detailed physical and chemical data in high-temperature (e.g., >1,000° C.) sections of such systems. For example, to further improve the performance and reliability and to reduce the pollution of turbine engines, robust sensors and sensor networks are needed for next-generation turbine technology to enable (i) obtaining detailed thermo-mechanical data to refine engine designs, (ii) providing online, real-time monitoring, and (iii) providing intelligent controls to make the engines “smart”.
Currently, several technologies are under development for measuring the physical and chemical parameters within turbine engines. Optical-based non-contact technology is known for determining these parameters. However, optical-based non-contact technology has been shown to lack the necessary measurement accuracy and typically breaks down over time. Another technique measures these parameters without disturbing the work environment comprises using miniature sensors. Silicon carbide (SiC) and silicon nitride (Si3N4)-based ceramic microsensors have been investigated for high temperature and harsh environment applications. However, these sensors are restricted by limited fabrication methods, high cost, and a limited operation temperature range (typically <800° C.).
Polymer-derived ceramic (PDC)-based sensors and sensing systems using such materials are also known. PDC materials are generally formed by the processing of materials referred to as “preceramic polymers”. Preceramic polymers are conventionally defined as polymers whose backbone contains C and at least one eteroatom (usually Si) that provides a ceramic residue (the PDC) through the elimination of organic moieties by breaking of C—H bonds, and release of H2 and CH4 and other volatile compounds. The term “eteroatom” is used to indicate any atom of a cyclic molecule or of a cyclic portion of a molecule or ion that is not carbon. The polymer-to-ceramic conversion is achieved either thermally (pyrolysis) or non-thermally (for instance by irradiation with ions), usually processing in controlled atmosphere. Polysiloxanes, polycarbosilanes, polysilanes and polysilazanes are some of the preceramic polymers currently available commercially, and they allow production of SiO2, SiOC, SiC, Si3N4 and SiCN ceramics.
In one disclosed system for measuring the temperature or strain in an aircraft, PDC-based sensors are wired to a signal processing system. This system senses a resistance change due to the temperature/strain change experienced by the sensors. A limitation of the wired sensing arrangement is that it cannot be used for measurements in difficult to reach locations, such as important sections in turbine engines such as the turbine blades, and sections that are blocked by the turbine blades. There is thus a need for new high temperature (e.g., >1,000° C.) capable sensors and sensing systems that can sense parameters in any section of a turbine engine, or in other space-limited high-temperature and harsh environment applications.